In 1309 {July} 16, Robert {Clifford} was granted, by Edward II, (In year 2 of his reign) a Royal licence to crenellate Pendragon (Pendragon Castle)

"Mandate to make letters to Robert ... that he may crenellate his castles of Brouham and Pendragon, C. Westmoreland."

Granted at Langley,

A fortified tower-house on a spur with deep ditch from circa 1173 with later additions and alterations. A licence to crenellate was granted in 1309, to Robert Clifford, and it is possible that the castle was enlarged at this time. The enrollment, the the Chancery Warrents, is mutilated.

Original source is

• Calendar of Chancery Warrents (1244-1326) p291

(In fact, the original source given is usually a transcription/translation of what are precious medieval documents not readily availably. It should be noted that these transcription/translations often date to the nineteenth or early twentieth centuries and that unwitting bias of transcribers may affect the translation. Care should also be taken to avoid giving modern meaning to the medieval use of certain stock words and terms.)

Significant later source are;

• Emery, Anthony, 1996, Greater Medieval Houses Vol1 (Cambridge) p263
  Jackson, M.J.,1990, Castles of Cumbria (Carel Press) p78-9

More details about licences to crenellate can be found here.

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